would cut the deficit by $200 billion over ten years. supporters say the change wouldn't cut benefits. >> if we're making the change to reflect what is the real cost of living, as opposed to a different one, then you are not reducing them; you're just truing up what you should be getting. not something that-- i hate to use the term-- that might be inflated beyond what it should have been. >> reporter: this so-called technical fix will shave a quarter of a percentage point off social security's annual cost of living increase, and that difference adds up over time. some worry that will hurt the very old. >> it cuts real benefits. if somebody is getting fewer dollars in their check, that's real to them. and for people who are sliding progressively farther behind prevailing living standards, which is true of those out of the labor force for a very long time, it's about as real as it gets. >> reporter: but the change to a chained c.p.i. is easy to do, and that means it could be packaged into a deficit agreement quickly if there is bipartisan